Halorussus halobius sp. nov., Halorussus marinus sp. nov. and Halorussus pelagicus sp. nov., isolated from salted brown alga Laminaria

Four halophilic archaeal strains, designated H08-83(T), LYG-36(T), DLLS-82 and RC-68(T), were isolated from the salted brown alga Laminaria of three different origins (Dalian, Lianyungang, Dalian and Rongcheng) in PR China. All strains had pleomorphic rod cells that were motile, lysed in distilled water, stained Gram-negative, and formed red-pigmented colonies on agar plate (except for DLLS-82, which formed white colonies). Based on phylogenetic analyses of the 16S rRNA genes, strain HD8-83(T) was closely related to Halorussus litoreus HD8-51(T) (97.9% similarity), strain LYG-36(T) and DLLS-82 to Halorussus rarus TBN4(T) (94.4% and 94.7% similarities, respectively), and strain RC-68(T) to Halorussus salinus YJ-37-H-T (96.9% similarity). Results of phylogenetic analyses based on rpoB' genes and 728 concatenated single-copy orthologous clusters also showed that these strains formed three different branches and clustered tightly with the Halorussus members. The average nucleotide identity, average amino acid identity and in silico DNA-DNA hybridization values between strains LYG-36(T) and DLLS-82 were 98.9, 98 and 92.4%, showing that they were different strains of the same species. While those values between the isolates and other Halorussus members were below 84.7, 82.9 and 28.9%, respectively. Based on the phenotypic, chemotaxonomic and phylogenetic properties, strains HD8-83(T), LYG-36(T), DLLS-82 and RC-68(T) represent three novel species of the genus Halorussus for which the names Halorussus halobius sp. nov. (type strain: HD8-83(T)=CGMCC 1.15334(T)=JCM 31110(T)), Halorussus marinus sp. nov. (type strain: LYG36(T)=CGMCC 1.13606(T)=JCM 32952(T); reference strain: DLLS-82=CGMCC 1.13604=JCM 32951) and Halorussus pelagicus sp. nov. (type strain: RC-68(T)=CGMCC 1.13609(T)=JCM 32953(T)) are proposed.